Electrical circuit tester



July 20, 1948. E. A. FUGLIE 2,445,557

I ELECTRICAL CIRCUIT TESTER Filed oct. 22,1945 2 sheets-sheet i I9 Inventor-'z July zo, 194s.

Filed om. 22, 1943 E. A. FUGLIE ELECTRICAL CIRCUIT TESTER 2 Sheets-Sheet 2 -HIIHIIIIIIII Y 53 S2 Y fllrLvzntor:llso X jELmerfAFuglia ...break occurs. tedious and dfifcult-operation, oftenconsuming a Patented July 20, 1948 ris-fn PATENT k l `2,445,667 .l l

.ELECTRICAL CIRCUIT ,TESTER fElmer A. L{lug-lie, --Wi.nona, y"#Minn., :assigner :to

Wi-nona 'E001 'Manufacturing f: Company, NVil ,Lr-iena, Minn.,..a. .corporation of, Minnesota Appiicationctoher 22, 1943, Serial No.' 507,346

system .`of.an automobile, wherein the system litself is now eXtensiveand complicated and tinl .wiresaresubjectedjtoheayy vibration and strain. When a shortoecursiwhere the current is supplied roin a battery, as in an automobile Wiring Msystem, lthe v battery is drained ,of its electric potential which isusuallythe first notication .givenef the.y existence of .the short. l.frequently hap-pen that,:withoutashortfthe conu ,.ductor .wire` mayrbreal: .inside of .the insulation.

Or, it may .This cuts .oli` .current to be supplied throughV that particularlwireand is indicated :insuch aernanjner.,as a lamp yer light aiIingV-tofgluw .when

switched on, even -though testing shows the lamp ,to .bein good lighting condition. lnleither of .these contingencies it-is necessary-to flocateethe point inthe `Wiring systenifwhere ythe shorten the rllhis heretofore has proved Aa large amount of time A.and resulting :in serious i expense.

flfhave :discovered .and invented an, limplement uhaving meansI :for :piercing the: insulation about `the conductor so asl/to contactnthe Ycondire/ter itself incombination with a `pretectelzl vamnfter structure, whereby .when the insulatien pierced Iltheaexistence binnen-existence of current-in the Wirefand of lshorting -or non-snorting current will .berevealed and the point where such break or :snorting exists will lbe located.

.Itfis a principal object of lmy-invention;thereutore/to provide. an instrument having a sharp Ypointedplunger and `means for Areceiving an insulated electricconductor so that thernetal point of the plunger may be 'caused :to piercegthe in- @wherebyWhen/*current is* located in the conductrfi-ngwirey the Aammeter needle will indicate the vipresence@fissatidcurrent.

Itis a further-object of -rny invention to' proyide isa'id .rammeter :with a built-in resistance klwhichzxwgill eprotect Hit V41and the Wiring and :the

operator when the `piercing point engages *la shorted wire.

`It is afurther object of VAmy inventionfas'above noted, to control the current passingv therethrough so as-to indicate the-'charaeterfof eur- It isa further obieet of my inventionto-mount the plunger upon astandard having ahookei-ike extension at fan angle lto the length 'lof the standard atene end i-nv thepatfhof movementof rthe sharp end of the` plungen so thatea wirehel'd "It is -aiurther vobject of my invention-to provvideI on the `hook extension' -someniea-nsfor receiving the insulating lconductorto -positiont`f1t inthe -path ofA they pointedcendof the plunger-iso that vwhen'the fpm-ngerV is forced l upon the-wire it will `pierce the insulationHar-id the `'I netail `end thereof Will Contact the-conductor wire within the insulation.

Itis -afurt-her objectof-my invention to provVide Vthe standard for *carrying* the plunger with f linger *holds andthe vplunger with a nhead engageable fwith lthe inside of the hand and ,with a spring surrounding Ythe lplunger between :a ubraelset on the standard and mancati-whereby the plunger can-be'fforced 'forward'to pierce the insulation `to a ywire* conductor .and Will b e. re -stored to Aan operativeypostion Whenjpressure upon it is released.

It is a further .object of .my invention to `proi-vide Vaconductor cable wired Yto the resistance and Athe ammeter needle. control, which ,is ,provided with' aI clip adapted .to be Asecured .uponlany suitable 'part which may be a source ,of electrical current; .such for example as thestarterftermiynal.

The full objects and advantagesofmy invenof givenin'the appended specication. and the novel features .by 1leans of which .,these,im portant objects andedvantages arerealizedlwill lbe particularlyy pointed out in -the..claim.

In the drawings illustrated an ,application of my invention in one form:

Fig. 1 is a plan View of my instrumentfor locating shorts and ;break.s,.vie.wed at. the front .of theammeter.

.Fig. 2 is a side elevation View ofiny instrument beingan edge view of what .is showni-nFig. l..

Fig. 3 is a sectional view aken on -line 3-.3.,of Fig. 14 and vviewed in. the .direction othe ,arrows- Fig. 4 is a sectional View takenenlineA--A'pf 3 Fig. 3, and viewed in the direction of the arrows.

Fig. 5 is an enlarged sectional view taken through the ammeter case and along the longitudinal plane of the plunger and the standard.

Fig. 6 is a diagrammatic View of a wiring system of an automobile showing diagrammatically the use of my instrument in locating breaks within the insulation.

Fig. 7 is a diagrammatic view of part of the wiring system of an automobile showing the use of my instrument in locating a sh'ort.

Referring particularly to Figs. 1, 2, and 3, I provide a standard I0. Secured to the upper end of this standard is a transverse bracket II whi-ch is formed with a short ear I2 on one side of the standard and a long ear I3 on the other side of the standard. There is also formed upon or secured to the bracket II a pair of finger holds I4 and I5. These linger holds are curved, as clearly shown in Fig. 1, and are adapted to receive the first two iingers of th'e hand. Extending through the bracket II in the position indicated in Fig. 3 isa plunger rod I6 which is substantially inside the plane of the inner edges of the finger holds I4 and I5. This plunger also extends through and is guided by a bracket I1 on the standard ID near the outer end thereof, being held in parallel relation thereto, as clearly shown in Fig. 2. Th'e plunger is adapted to extend a considerable distance above the outer face of bracket II as indicated at I8. The plunger has on its outer end a head I9 adapted to be positioned in the palm of the hand when the nger holds I4 and I5, and the plunger is surrounded by a compression spring 28 which is positioned between the head I9 and the outer face of the bracket I I and tends to push the plunger outwardly. A stop pin 2| extending through the plunger I6, Figs. 2 and 3, is thus brought into engagement with the under side of the bracket I I, holding the plunger in normal retracted position.

The free end of standard I0 is turned inwardly in a projection 22 extending substantially at right angles to the standard I8 and being in the plane of the axial centers of standard Ill and plunger e I6. The plunger I6 is formed with a needle-like point 23, Figs. 1 and 2, which is directed toward the extension 22 so that when the plunger is projected by operation of the hand upon the ringer holds I4 and I5 and the head I9, the point 23 will be moved directly toward the axial center of the projection 22.

A wire h'olding guide 24 is formed in the body of the projection 22 facing the point 23 of the plunger I6. This holding guide may be of differ ent forms, but I have found a V-shaped cut across at right angles to the extension 22 to be very satisfactory, with the point of the V at 25 directly in the line of travel of the point 23 of the plunger I6, as clearly shown in Fig. 2. In this manner an insulated wire, such as indicated at 26, Fig. 5, when laid upon the V 24 will be centered with respect to the point 23 so that it may readily be forced through the insulating covering 21 to the conducting wire 28, all as shown in Fig. 5.

As best shown in Figs. 4 and 5, there is secured to the long ear I3 of bracket member II an ammeter comprising a casing 29, a glass face 30, and a dial 3|, Fig. 5, having thereon an opening 32. The curved edge 33 is provided with a scale sh'owing a center figure O indicating no current, two intermediate positions at the sides thereof designated as L, meaning normal lamp current, and

two calibrations still further removed designatedl as S, indicating short current.

A post 34 is secured to the bottom 35 of the casing 29 and is insulated therefrom by strips of Bakelite or other insulating material 36 and 31. An insulated wire 38 has its conducting wire 39 secured to the post 34 by means of a nut 40, Figs. 2 and 3. The conducting wire 39 is connected to and in circuit at the free end of cable or insulated wire 38 with a clip piece 4I. A second clip piece 42, Fig. 1, is pivoted to the clip piece 4I at 43. These pieces 4I and 42 h'ave reversely turned finger pieces 44 and 45 which are normally held in contact by a compression spring 46 located between the clip pieces 4I and 42. By squeezing on these pieces the spring may be compressed and the jaws 41 and 48 of the clip thus be opened to be placed upon and in conducting relation to any connection with the source of current, as a battery. In practice this connection may conveniently be made with the starter terminal, indicated at 49 in Fig. 7.

Within the ammeter casing 29 and secured to the bottom 35 thereof is a resistance piece 50. This resistance piece has one arm 5I which receives the post 34 and is in circuit with the contact wire 39 in cable 38 leading to the contact clip and the source of electric current to which the clip is attached. The resistance 50 has a second arm 52 which is secured by screw post 53, Fig. 4, directly upon th'e back Wall 35 of the ammeter case and thus is in circuit with the ear I3 and bracket II and through contacts of that bracket and of spring 20 with parts of the plunger I6 is also in circuit with the plunger and its piercing point.

The resistance piece 58 has secured thereto or formed as a part thereof an arm 54 extending normal to or at right angles to the resistance piece 50 and provided with a backward extension or lip 55, Fig. 5. Between th'e resistance piece 50 and the lip 55 is pivotally mounted a pintle 56 which has secured thereto the shank 51 of an indicator needle which has the needle portion 58 brought to the upper part oi the ammeter chamber close to the dial 3l and so as to move along the opening 32 th'erein. The pintle 56 has a mounting which permits a movement of the needle 58 upon the pintle with negligible resistance. Wings 59 and 60 are formed as a part of the arm 54 and leave an opening 6I through which the needle shank 51 extends. The wings 59 and 60 operate as stops to limit the swinging movement of the needle shank 51 and its needle portion 58, as clearly appears in Figs. 4 and 5. This is a standard ammeter construction, which need not further or more in detail be described. It is suicient to say here that the needle -construction 51 and 58 is normally balanced in position so that if no current passes through the resistance 50 the needle end 58 will point to zero on the dial 3|. If moderate current flows, as to a light, the deiiection will be slight or to the point on the scale indicated as L. But if strong current ilows, as for a sh'ort, the deection will be correspondinglg greater to the point on the dial indicated as (l .H

The operation of the construction is shown diagrammatically in Figs. 6v and '7. The operative switch 62 as the light switch is thrown into circuit making position. All other switches are turned off. If, for example, a, condition arises in which the headlights do not operate when the switch .62 is closed for lighting, these headlights 63 and 64 either on the driving or highlight circuit 65 or the dimmer circuit 66, and one or the other of these lights, for example the driving lights, do not glow, even though testing shows that the lamps are perfectly operative, it will be evident that there is a break in the wire some where. To nd the break the instrument is conn nected to the battery circuit, as'to the starter terminal at 49, and the instrument is applied to the insulated highlight wire 61 at a point S8 and the needle point caused to pierce the insulation and so to contact the conductor wire. If ammeter needle is shifted to L, meaning light, the operator is informed that the break is farther removed from the lamp.

The operator will continue to pierce the insulated circuit wire 61 at various points until finally he reaches a point indicated at 69 where the ammeter needle remains at zero. The operator then is informed that the break is between the point of earlier testing the wire as at 68 and the point of last testing the wire as at 88. The break is thus located and repair can be made. This, of course, can be carried out effectively for other circuits, as the dome light circuit T0 and the tail light circuit 1I, In this manner the location of a break in the wire inside the insulation may be quickly discovered and the repair made with a minimum expenditure of time and expense.

If there is a short which has drained the battery, it almost always results from a place where the insulation of the circuit wire 26 has been worn away so that the conducting wire 39 is brought into Contact with a frame member, as member indicated at 'I2 in Fig. 7. When such a short exists the` frame piece must, of course, be between the source of electric current and the implement to be energized, as one of the lamps.

If the insulation is pierced and the conducting wire contacted between the short and the lamp or other implement to be energized, or at any other point on the wire between the switch terminal and the short, heavy current will go through resistance 50 with the result that the needle will shift to the position indicated by the letter S indicating that that wire is the one in which the short exists and following the wire through the short can then be located.

Where the short exists in a lighting circuit, the particular wire which is shorted usually can be found by merely touching with the point end of the tester the connecting terminal on the light switch. As illustrated, the wire 38 is connected with the battery and successively touching the terminals at the light switch will cause the lamps to glow if no short is present and will indicate at L on the dial, but when a short is present in the tested lighting wire the light will not glow and the needle will swing to the point designated as S indicating a short in that wire. Otherwise, the operator will work under the hood,

6 preferably from the steering wheel side, where most trouble is to be found, and will successively pierce diiferent wires until a short is indicated.

The advantages of my invention will suii'ciently appear in the foregoing analysis and description given in the specification. It is a simple, inexpensive construction which can be put in the hands of garagemen and repairmen generally at a relatively low cost, and by the use of which in a simple series of successive testings the broken wire or short quickly can be located.

I claim:

A short-and-break locator for electric wiring in position such as the insulated conducting electric wiring of an automobile, comprising a sup port formed of an integral elongated bar, an inte gral portion offset at right angles from said bar provided with a notch to receive and position an insulated wire, a plunger rod mounted for endwise movement close to and parallel with the bar having a sharpened point in longitudinal alignment with the center of said notch, said plunger extending beyond the outer end of the support and having a palm-engaging knob on its outer end, a spring about said extended portion for forcing the plunger away from the notch, finger grips rigidly connected to the standard so the appliance can be held in one hand of an operator for forcing the point through the insulation to cause the point to contact the conducting wire within the insulation, an ammeter held by the standard close to the finger grips and plunger, and an elongated wire connected with one terminal of the ammeter having thereon a clip adapted to be put in electrical circuit connection with the source of electric current for the electric Wiring the rod and the plunger point being in circuit connection with the other terminal of the ammeter.

ELMER A. FUGLIE.

REFERENCES CITED The following references are of record in the 

